Since it was introduced to the UK nine years ago, groups have popped up in Hastings, Hertford, Huddersfield and almost everywhere in between. It can only be a matter of time before the celebrity yoga set joins experienced "shakers" and jets off to the ashram in Bali where it all started with the "enlightened master" Ratu Bagus.

"For the Westerner, it is a wonderful way to relieve stress in a physical way," says Kamini Hola, a former businesswoman in Brussels who gave it all up at the age of 34 to become a yoga teacher. It was Kamini who first demonstrated her hour-long daily practice to me.

Most weekly group shaking sessions last for two hours, including a "clearing" prayer at the end, a short meditation and a group circle chat. Kamini's practice involves keeping her feet firmly on the ground, while vibrating like a child doing an impression of receiving an electric shock. It's all rather reminiscent of Eighties pop sensation Shakin' Stevens.

I join a shaking group in Hastings. Many of the participants have just come back from a week's retreat in Rome, where Ratu Bagus (meaning "Good King") was helping 230 Europeans through their various "processes". The aim was to shake out physical and emotional ''blocks" and ''get the energy".

"The block is something negative that complicates the functions of our body," says Ratu Bagus, who believes that all sickness comes from the mind. "The technique is to get the energy flowing in our bodies and to surrender to the energy and accept it with a smile."

To help them receive this energy, shaking groups recreate a sort of rave party, complete with trance music, candles, joss sticks and a poster of the enlightened master. Some even use tobacco, albeit in its pure herbal form, which they place between gum and lower lip to help them focus.

It's not for me, although I'm all for people dancing, laughing hysterically and screaming when they feel like it. My main concern is that although my visit leaves me feeling energised, those who seem to be "processing" strongly, in an almost religious trance, are supported only by other group members. Surely this level of intensity should carry a health warning?

"There is support within the group," counters Kamini. "Many shakers are trained therapists, and in my experience the 'energy' and its intelligence will only give us what we can cope with."

For a second opinion, I ask cognitive behavioural psychotherapist Dr George Fieldman. ''Meditation certainly has its place in enhancing mental wellbeing," he says. ''But I wouldn't ask any of my clients to embrace this particular version until it has been subject to a scientific evaluation and shown to be safe."